Recording system



Patented Feb. 2, 1943 UNITED STATES PATENT OFFICE 'ascoanme srs'rmLivingston Middleditch, Beverly mm, Calif.

Application July 5, ms, Serial No. 217,548

Claims. (cyan-11) This invention relates to a method of recordingimpulses, and more particularly to a method of producing a sound recordfor reproduction by photosensitive cell and electrical means.

advantagethat a recording must be processed 1n the photographiclaboratory before it is ready for It is an object of this invention toprovide a method of producing a record that can be compactly stored andthat can be played back imi It is common to record sound, orother im- 5pulses having frequencies comparable with sound medlately, without the.delay or cost of photofrequencies, either by the original phonographicgraphic developing or other processing. method of sound-on-waxrecording, or by the Another object of this invention is to providelater developed photographic method of sounda method of producing arecord that can be on-fllm recording.. While each of these methodsreadily edited, corrected, or rearranged after reis admirably suited toparticular purposes, they cording. I each have certain disadvantages,and there are In order to accomplish these objects, use is manyevery-day instances in which sound remade of a printing member thatoperates mecording would be desirable to which these methchanically tomark a moving tape in accordance ods do not conveniently or economicallyapply. with the impulses to be recorded. This marking A few suchinstances are: for recording extended may be accomplished through aninking medium dictation, conferences, judicial proceedings, lecor bycarbon paper. It is another object of this tures, radio programs, andtelephone conversainvention to provide a simple form of recorder tions;for taking telephone messages when no whereby these impulses may produceeither a one is present; and as a more rapid medium than variabledensity record, or a variable area record, Braille printing for the useof the blind. or a combination thereof. A

One obstacle in the way of extensive everyday Although the primaryobjects stated have to use of sound recording in these fields has beendo principally with the making of sound records, the fact thatrecording. especially by the photoit is a further object of thisinvention to supply graphic method, has been a highly technical as aconvenient method of recording varying improcedure and not readilysimplified for the laypulses of any sort, such as those accompanyingman. Another obstacle no less serious'has been telegraphic transmissionof code, facsimile, picthe high cost of the record carrier per hour oftures, transient electrical phenomena, sonic conrecording time. Wax andacetate discs or cylintrol of automatic machines or devices, etc.,either ders are expensive, and, if kept as permanent for purely recordpurposes or for later utilization records, inconvenient and expensive tostore. by photo-electrical means. Photographic film is. expensive initself, and to The record or sound track is formed by a sucthis must beadded the cost of development and cession of marks formed on therecordblank by other processing. Paper tape, inch wide, as movement ofthe recordingmember in a direction used for the record carrier inseveral emboditip which has a component normal to the surface of mentsof this invention, costs but a small iracthe blank, in W t0 im pp i d tothe tion of the amount per hour for the record carmember by suitabletranslating mechanism. rier when using either of these other methods.Thus, the spacing of the marks depends on the I An object of thisinvention is to provide a frequency of the impulses, or sounds, beingremethod of recording so simple in operation that it 40 corded, while heWidth 01 marks p n can be carried out by a person relatively inex on thestrength of-the impulses or volume of the perienced (or even unattended)and suitable for sound. K v a recording in the home, school, or businessoflice. Where a recording member having a straight Another object ofthe'invention is to' provide edge, as member I of Fig. 1 or member I8 ofFig. a method of recording so economical in operation 3, is used, asound track ll of uniform width and as to make it suitable for extensiveapplication in variable density is formed. It a recording memthe fieldsmentioned above. her which has an arcuate edge is used, as member Theaound-on-wax method has the disadvan- 22 ofFig. 4, or member 21 of Fig.5, the sound We of, limited Fl -yin! time on a single recording trackwill be a combination of variable area and surface, \mless the surfacebe of unreasonable variable density, since the recording member willsize, and it on'ers no easy method of editing or act as before toproducea variable density recrearranging a record after it has beenmade. ord. In addition, however, the curved recording Bound-on-iilmrecording overcomes these two member will when it makes a deep im r n indimculties, but atthe same time it has the disa response to strongimpulses, make these impressions longer,- as well as denser,as'indicated in sound track ill of Fig. 4, than the impressions made inresponse to weaker impulses. Thus it may be said that the length of theindividual marks of the sound track, or the width of the sound tra is afunction of the pressure exerted by the recording member. The verypractical advantage of such 2. combination track over either variablewidth or variable density alone, is that it increases the volume rangeof impulses that can e recorded on 2. given width of sound track. It ishighly desirable that the sound track be narrow, say only inch wide asin sound motion pictures.

This invention possesses many other advan tages, has other objects whichmay be made more cushy apparent from a consideration of sew oralembodiments of the invention. For this purpose there are shown a fewforms in the drawing accompanying and forming part of the presentspecification. These forms, which illustrate the ciples of my invention,will now be detail; but it is to be understood. that this no ledescription is not to be taken in a limiting sense, s' ce the scope of myinvene by the appended claims. i rring to the drawing:

1 shows the printing member in schema ic operative relation to a tape,and a that constitutes a single elementary impression;

shows in schematic form. a recording .iue suitable for use with themethod of re "cg that comprises this invention;

3 shows in schematic form an embodiment oi the invention in which theprinting member is vibrated normally to the face of the record carrier,giving a variable density recording;

Fig. 4 shows in schematic form another embodiment of the invention, inwhich the face of the printing member is 9. plane curved knife edgevibrated normally to the face of the record carrier, and giving a recordthat is both variable area and variable density;

Fig. 5 is s. schematic section of another form of the invention in whichpigment is supplied by a carbon paper ribbon passed between the printingface and the record carrier;

Fig. 6 is a schematic section of still another form of the invention inwhich the printing face is the periphery of a rotating sharp-edged discsupplied with ink by an inking roller; and

Fig. 7 is a cross section of an alternative form of printing member inwhich ink is supplied to a slit-shaped recess (here shown asan annularrecess between two rotating discs), the printing being done fromintagllo; and

Fig. 8 is a schematic partial sectional view of the form of theinvention illustrated in Fig. '7, taken along a plane normal to Fig. 7.

In Fig. 1 a record blank I is shown as receiving a record impression.This record blank will usually be in the form of a flexible paper tape,but any other thin flexible material capable of receiving theimpression, such as Celluloid, or even thin metal, may be used. If thetape I be made of material that is transparent, such as thin Celluloidmentioned, duplications of the recorded material may be obtained byordinary photographic printing processes. Metal tape may be useful inconnection with reproduction by other well known methods.

This tape I, as illustrated in Fig. 2, may be fed from a supply roll 2past the recorder station 2 onto a driving roll 4, and finally to a takeup roll 5. The recorder 3 in Fig. 2 is illustrated as being a providinga. variable density record.

subjected to the impulses from a source of signals 6, through anamplifier l. The recording of these impulses is accomplished by theprinting process now to be described.

In Fig. 1 the impression or printing member 8 is shown generally asarranged transverse to the surface of the tape 1 and as having a narrowrecording edge 9. This edge is transverse to the direction of the travelof the tape 1, although not necessarily at right angles thereto. Byurging the impression member 8 transversely against "the surface of therecord blank I, an impression or printing effect may be obtained. As thetape is moved, the impression member 8 may be actuated toward the recordblank with a pressure corresponding to the impulses to be recorded andto print a succession of lines or striations. One such line isillustrated at H). The actual printing or marking may be accomplished bythe aid of carbon paper, or printing ink in a manner be describedhereinafter. By appropriate choice of speed of the tape I post theimpression member 8, satisfactory recording over a rather wide range ofaudio frequencies is attained.

In the diagram of Fig. 1, the broad idea of providing a printing effectby causing a printing pressure to be applied between the record blank land the printing member 8 is illustrated.

In Fig. 3, the motion of the impression member 18 is in a directionillustrated by arrow 11, corresponding to a direction having a.component that is normal to the surface of the tape 18. In thisinstance, the record I9 is formed of a substantlally continuous seriesof closely spaced marks This is accomplished in'view of the fact thatthe greater the printing impression produced by the impulses, the denserthe individual marks are.

In Fig. 4, the record 2| on the moving tape or blank 26 is a combinationof the variable area type and the variable density type. In this casethe individual marks, comprising the series of marks in the record, havea variable length as well as variable density. This is accomplished byproviding the impression member 22 with a narrow arcuate printing face23, the curve of the face lying in a plane which is transverse to thesurface of record 20 and transverse to the direction in which record 20moves. As in the preceding form, impression member 22 moves in adirection having a component normal to the surface of the record 20. Byappropriately supporting the moving tape 20 on a resiliently deformableplaten, the resultant record .produced by varying the pressure betweenmember 22 and the tape 20 takes the form as illustrated by the rec- 0rd21.

With light pressure between the printing member 23 and the platen arelatively narrow contact is had between the arcuate face of theprinting member and the blank, and with heavy pressure the platen yieldsand afiords wide contact between them. After the heavy pressure isremoved the resilient platen returns to its original form and the narrowprinting contact is restored. Thus the variable width feature of therecord 2| is obtained, a

The resiliently yielding platen is useful also in connection with thevariable density feature of the record 2 I, or with the purely variabledensity record I 9 in Fig. 3, inasmuch as it permits greater amplitudesof motion between the printing membar and the record blank. If a. hard,unyielding platen is used a series of sine wave impulses is distortedand recorded as a square topped wave form, that is maximum printingeflect is too quickly built up in the positive direction, and in thenegative direction the pressure is totally released and the printingmember Jumps clear of the record blank. Only at very low amplitudes isfaithful recording of impulses possible with a hard, unyielding platen,the volume range in face or thickness of the record blank are minimined.In Fig. the platen 24 is shown as accommodated within a channel formedin a stationary support 25. Disposed and movable over the platen 24 isthe record blank or paper strip 26. The printing or pressure member 21,shownin this case as provided with the narrow arcuate recording edge 28,is intended to contact the reverse side of a strip of carbon paper 29.This carbon paper 29 is interposed'between the tape 28 and the recordingedge 28, and is preferably fed slowly as its marking pigment is used up.The recording member 21. is indicated as guided in this instance formovement substantially normal to the surface-of the tape 26, as in thestationary guides 30. This motion, as indicated by arrow ii, is producedin response to electrical impulses, as for example by the aid of a voicecoil 32 mounted on a support 33 attached to the bottom of the impressionmember 21. The voice coil 32 is shown as disposed within the narrow airgap formed by the magnetic pole pieces 34 of a dynamic speaker unit. Ifdesirable, a compression spring 35 may be utilized, providing normalpressure upon the member 21, even when no impulses are being received.However, such initial pressure may be provided in other well known ways,as for example by the aid of a direct current passing through the voicecoil 32, supplementing the current impulses to be recorded. If a springis used, its stiffness should be related to the compliance of theyielding platen, the mass of the moving parts, and the frictionalresistances, so that the resultant record shall have the desiredfrequency response characteristics. Part of the control of frequencyresponse can be obtained .by suitable electrical design of the amplifier1.,

and part by suitable mechanical design of the recorder itself.

In this form just illustrated, the carbon paper 20 interposed betweenthe record blank 26 and the impression member 21 serves as a medium forproviding the marking of the record, such as illustrated in Figs. 3 and4. The resilient platen 24 insures that as the pressure upon theimpression member 21 varies in accordance with the impulses to berecorded, the length of the transverse marks is'varied, as well as theirdensity.

In the form of the invention illustrated in Fig. 6, the member itoperated by the dynamic coil arrangement 31, is shown as carrying theresilient platen 84 adapted to support the record blank or tape 39. Thisblank 39 is shown as urged against a printing wheel 44 supported on astationary axis. The inking roller 4| is inthe narrow printing edge ofthe printing wheel 40. The carbon paper, of course, is omitted. Here theplaten I8 and the tape 39 are preferably moved by the member 36, inorder that the relatively massive impression wheel 40 and its inkingroll 4i may be maintained on stationary axes. The periphery of theprinting wheel 40 is provided with a series of very fine serrations 44,

-- which serve to carry ink evenly across the area of contact with thetape. A smooth edged disc has a tendency to wipe off most of the ink atprinters ink, in order to render it more freely flowing.

In place of a thin disc impression roller, another type of printingwheel, such as illustrated in Figs. '1 and 8, may be utilized. The discs42 and 43 forming the printing wheel proper, are spaced slightly apartto form a capillary passage "between them. This capillary passage isintended to be fed with appropriate inking fluid through; an axialaperture 48. This roller structure may be driven, as by aid of a groovedpulley 41 joined in any appropriate manner to the hub 48 of the disc 43.The outer disc 42 is shown as threaded. over the threaded extension 49of the hub 48, and a check nut serves to hold this disc in place withthe proper narrow spacing between discs.

While this device may be used without rotation, it tends to gather dustand dirt from the moving tape and to become partially clogged. Rotationserves to wipe away the dirt and to continually present a fresh surfaceto the tape. In addition, centrifugal force helps gravity or otherpressure to overcome capillary attraction and resistance to the flow ofink through the narrow passage between the discs, so that an extremelynarrow intaglio inking surface is presented to the tape by the peripheryof the wheel.

In all the forms illustrated the record is ob tained immediately and canbe played back withtended to apply an appropriate type of ink to outdelay, by appropriate photoelectric means. In some instances thepressure effects produced by the printing member, such as the members 4,I6, 22, etc., may be used even without ink, to afiect .a sensitivephotographic film. It has been found that variations inpressure, such asproduced by the impression members, have generally the same eflect aslight. The tape carrying the sensitive film may then be developed in theusual manner to flx the record thereon.

What is' claimed is: v

1. In apparatus for recording impulses on the surface of a moving recordblank, a serrated printing wheel adapted to print on said blank,

resiliently yielding platen upon which said blank may be disposed, aprinting wheel formed of a pair of spaced wheel sections, and adapted tomake an impression upon the blank and against the resilience of theplaten, and means creating the printing pressure in accordance with theimpulses to be recorded.

5. In apparatus of the character described, a moving record blank, 9.means forming resilient backing for the blank, a rigid printing member.having a thin printing edge disposed transversely to the direction ofmovement of the blank, and means to move said printing member in adirection having a component normal to the surface of the blank to makean impression thereon against the resilience of the support and inaccordance with the impulses to be recorded.

LIVINGSTON MIDDLEDITCH.

